Buried in mid-winter, January generally portends the ramping up of bronchiolitis season in the majority of the United States. Of particular note for this season, the American Academy of Pediatrics has published a new clinical practice guideline, updated from the 2006 edition.¹

The guideline document is divided into three sections: diagnosis, treatment, and prevention. Only the diagnosis and treatment sections have relevance to emergency physicians. Specifically covered by these guidelines are infants ages 1 month to 23 months, but reasonable generalizations may be made beyond the upper limit of this population. As with all guidelines, it should be emphasized that these reflect reasonable practice principles, and acknowledging appropriate variation may be considered both acceptable and necessary.

The pattern toward simplicity starts with making the initial diagnosis. Bronchiolitis is a clinically distinct syndrome generally recognizable by history and physical examination alone. After confounders of upper respiratory illness and other diagnoses are adequately considered, classic tachypnea, wheezing, and rales in the proper context support the diagnosis. Assessment of the severity of bronchiolitis is best made, again, solely on the basis of clinical evaluation. The best predictors of complicated disease course, including apnea and critical illness, are underlying comorbid conditions such as prematurity, neuromuscular disease, or reported witnessed episodes of apnea.

The use of pulse oximetry has proven to be controversial as otherwise well-appearing children with bronchiolitis frequently display impaired oxygen exchange. The best evidence suggests utilizing pulse oximetry as part of a decision-making process to predict disease severity is not appropriate and even harmful. A recent trial published in JAMA systematically altered pulse oximetry readings of patients with bronchiolitis, displaying higher numbers to treating clinicians than actually present.² Patients randomized to such artifice had reductions in hospitalization without corresponding increases in adverse outcomes. The implication is that clinicians were giving oximetry readings too much importance compared to their clinical evaluation. These guidelines go on to state that supplemental oxygen is unnecessary unless ≤89 percent, and mild hypoxemia is reasonable.

No testing in the evaluation of bronchiolitis has been demonstrated to confer individual benefit. Viral testing for the etiologic agent, such as readily available respiratory syncytial virus assays, provides no additional prognostic information. Chest radiography is also of routine disutility, with no specific radiologic findings providing additive value for prediction of disease severity. Furthermore, use of radiography frequently identifies abnormalities leading to initiation of antibiotic therapy, which is unwanted, unnecessary, and obviously of no benefit for a viral process. Only children with severe or complicated symptoms are appropriate for radiography.

The best predictors of complicated disease course, including apnea and critical illness, are underlying comorbid conditions such as prematurity, neuromuscular disease, or reported witnessed episodes of apnea.

One of the biggest changes from the 2006 guideline, and almost certainly part of most current routine practice, is a trial of bronchodilator therapy in children suspected of viral bronchiolitis. The authors use the phrase “overall ineffectiveness outweighs possible transient benefit,” which very precisely describes the reasonable elimination of albuterol (or salbutamol) from therapy for children with bronchiolitis. The limited subjective improvement observed in trials did not translate to any meaningful or durable clinical improvement and only subjected patients to, albeit mild, adverse effects of beta-agonist therapy.